机器人学基础第6章机器人传感器ppt课件

1、中南大学中南大学蔡自兴，谢蔡自兴，谢 斌斌zxcai, zxcai, 20192019机器人学根底机器人学根底第六章第六章 机器人传感机器人传感器器1Ch.6 Robot SensorsFundamentals of RoboticsFundamentals of RoboticsCh.6 Robot Sensors26.1 Introduction to Robot Sensors 6.2 Internal Sensors内部传感器内部传感器 6.3 External Sensors外部传感器外部传感器 6.4 Robo

2、t Sensor Application Considerations 6.5 SummaryCh.6 Robot Sensors6.1 Introduction to Robot SensorsApplication of multi-sensors in mobile robot6.1 Introduction to Robot SensorsRobot sensors can be divided into two main categories:Internal stateDetect position and orientation in the coordinate of the

3、robot itself, deal with the detection of variables such as arm joint position, velocity, and acceleration.External stateLocalize the robot to the environment, deal with the detection of variables such range, proximity, and touch.6.1.1 Classification of Robot Sensors6.1 Introduction to Robot SensorsM

4、ost needed sensory abilities for robot:Simple Touch: detect whether the object is there or not.Compound Touch: detect the size and shape of the object.Simple Force: detect force along one direction.Compound Force: detect forces along multiple directions.Proximity: non-contact detection of objects.Si

5、mple Vision: detect feature such as holes, lines, and corners.Compound Vision: recognition of object.6.1.1 Classification of Robot Sensors6.1 Introduction to Robot Sensors66.1 Introduction to Robot Sensors 6.2 Internal Sensors内部传感器 6.3 External Sensors外部传感器 6.4 Robot Sensor Application Consideration

6、s 6.5 SummaryCh.6 Robot Sensors6.2.1 Position/Displacement Sensors 位置传感器位置传感器 A position sensor is any idea that permits position measurement. It can either be an absolute position sensor or a relative one (displacement sensor). Position sensors can be either linear or angular.Inductive Non-Contact

7、Position Sensors, String Potentiometer, Linear variable differential transformer (LVDT) , Potentiometer, Capacitive transducer, Hall effect sensor, Proximity sensor (optical), Grating sensor, Rotary encoder (angular), Photodiode array, etc.6.2 Internal Sensors6.2 Internal Sensors1. Linear Potentiome

8、ter 线性电位计线性电位计 Consists of a wirewound resistor (or a thin film resistor), and a sliding contact point.6.2.1 Displacement/Position Sensors() /() / ()EeeLxLx(2)LeExE6.2 Internal SensorsA rotary encoder, also called a shaft encoder, is an electro-mechanical device that converts the angular position of

9、 a shaft or axle to an analog or digital code, making it an angle transducer. 2. Rotary encodera) 导电塑料型b) 线圈型6.2 Internal Sensors3. Electro-optical Position Sensora)光电位置传感器 b) 感光量曲线 6.2 Internal SensorsFind the relationship between the distance and the received light volume (shows in Fig. b) in adva

10、nce, we can measure the displacement x of the light source. 1Absolute Optical Angle Sensor 光学式绝对型旋转编码器6.2.2 Angle Sensors6.2 Internal SensorsFor example, resolution of a 12 bit encoder is 2-12 = 4096, so we have a resolution of 1 / 4096 (for a round of 360 degrees). Absolute rotary encoders can also

11、 be used to detect angular velocity. By comparing current value and stored values, we can obtain the corresponding angular velocity. 1Absolute Optical Angle Sensor6.2 Internal SensorsCounting the number of conversions to calculate relative angle.Incremental rotary encoder can only measure relative a

12、ngle from initial value to current one. Therefore, in order to know the exact current angle value, some other methods (such as the absolute encoder) are needed to identify the initial value of angle.2Relative Angle Sensor 光学式增量型旋转编码器光学式增量型旋转编码器6.2 Internal SensorsIn this approach, no matter the cloc

13、kwise (CW) rotation, or counter-clockwise (CCW) rotation, output of the sensing light always alternate between H and L, so we can not get the direction of rotation.2Relative Angle Sensor6.2 Internal SensorsAdding another sensor (B) 1/4 cycle away from sensor A. Typically, when clockwise (CW) rotatio

14、n, signal A changes before B, vice versa.2Relative Angle Sensor6.2 Internal SensorsAttitude sensors are used to detect the relative relationship between the robot and ground. When the robot is fixed (just as the majority of industrial robot), there is no need to install such sensors. Attitude sensor

15、s are essential for mobile robots.Attitude sensors detect moving changes in position and orientation of the robot that can be used to control the robot implement desired instruction. 6.2.3 Attitude Sensors 姿态传感器姿态传感器6.2 Internal SensorsA gyroscope is a device for measuring or maintaining orientation

16、, based on the principles of conservation of angular momentum. 1电动机2角度传感器3转子4一弹簧 Shown right is a rate gyro. 1Gyro Sensor 陀螺仪陀螺仪6.2 Internal Sensorsgas rate gyroscope气体速率陀螺仪optical gyroscope光陀螺仪piezoelectric vibratory gyroscope压电振动式陀螺(shown on the right)2Other Gyros6.2 Internal Sensors196.1 Introduc

17、tion to Robot Sensors 6.2 Internal Sensors内部传感器 6.3 External Sensors外部传感器 6.4 Robot Sensor Application Considerations 6.5 SummaryCh.6 Robot Sensors6.3.1 Tactile Sensors 触觉传感器触觉传感器The prototype of robot tactile sensor is an imitation of human tactile sense of touch functions:Tactile sensePressure sen

18、seSlip senseForce sense6.3 External Sensors 内传感器内传感器6.3 External Sensors1Touch Sensor 接触觉传感器接触觉传感器Application: Touch sensors are equipped in the palm of the end-effctor in order to grip objects precisely. 6.3 External SensorsRobot pressure sensor can detect the pressure and its distribution through

19、an array of piezoelectric elements. (Eg. Springs (弹簧) for mechanical detecting).2Pressure Sensor 压觉传感器压觉传感器Applications: By smart control of pressure, end-effector can pick up not only fragile objects as glass cups, but also soft object as tofu and eggs.6.3 External SensorsSlip sensor is used to det

20、ect force and displacement in the vertical direction of the pressure. 3Slip Sensor 滑觉传感器滑觉传感器6.3 External SensorsRobot Force sensors can be divided into 3 categories:Joint force sensor, installed in the joint actuator, measure the output force and torque of the actuator itself, is used to control th

21、e feedback of the force.Wrist force sensor, mounted between the end-effector and the last joint, measure forces and torques on the end-effector for all directions.Finger force sensor, installed in the robot finger joints, measure the clamping force of an object.4Force Sensor 力觉传感器力觉传感器6.3 External S

22、ensorsDraper实验室研制的六维腕力传感器SRIStanford Research Institute研制的六维腕力传感器林纯一研制的腕力传感器4Force Sensor6.3 External Sensors6.3.2 Distance Sensor 机器人间隔传感器机器人间隔传感器 1 Ultrasonic Distance Sensor 超声波间隔传感器 Ultrasonic distance sensor is consisting of a transmitter and a receiver, which are both based on piezoelectric ef

23、fect (压电效应).6.3 External SensorsPrinciples of Ultrasonic Ranging- TOF (Time Of Flight ，时间行程法)超声波测距原理图超声波测距原理图1Ultrasonic Distance Sensor6.3 External Sensors1Ultrasonic Distance Sensor 6.3 External Sensors2Proximity Sensors 接近觉传感器接近觉传感器 A proximity sensor is a sensor able to detect the presence of ne

24、arby objects without any physical contact. A proximity sensor often emits an electromagnetic or electrostatic field, or a beam of electromagnetic radiation (infrared, for instance), and looks for changes in the field or return signal. The object being sensed is often referred to as the proximity sen

25、sors target. 6.3 External SensorsDifferent proximity sensor targets demand different sensors. For example, a capacitive or photoelectric sensor might be suitable for a plastic target; an inductive proximity sensor requires a metal target.2Proximity Sensors6.3 External SensorsResearch have shown that

26、 the visual perception of information accounts for 80% of what people perceived from outside world.Cells of human vision have the magnitude of about 108, is 3000 times to auditory cells(听觉), and over 100 times to the sensory cells of the skin皮肤触觉.6.3.3 Vision Sensors 视觉传感器视觉传感器6.3 External SensorsCh

27、arge-coupled device (CCD) is a major technology for digital imaging. Although CCDs are not the only technology to allow for light detection, CCDs are widely used in professional, medical, and scientific applications where high-quality image data is required.CCD (Charge-Coupled Device) Sensors6.3 Ext

28、ernal SensorsA total of 256 gray scale, from the Figure (a) to (f) followed by resolution of 512 512, 256 256,128 128,64 64,32 32,16 16.The impact of change on the image resolution6.3 External SensorsFigure (a) to (f) with resolution of 512 512, followed by 256, 64,16,8,4, and 2 gray levels.The impa

29、ct of change on the image gray 6.3 External SensorsFigure (a) to (f) followed by: 256 256,128-level gray scale; 181 181,64-level gray scale; 128 128,32-level gray scale; 90 90,16-level gray scale; 64 64,8-level gray scale; 45 45,4-level gray scale.The impact of changes in both resolution and grayscale6.3 External Sensor